Aprotinin reduces the need for blood products during liver transplantation

Antifibrinolytics reduces blood loss in thoracic surgery: a systematic review and meta-analysis

BACKGROUND

The purpose of this systematic review is to evaluate the efficacy of antifibrinolytics in non-cardiac thoracic surgery.

METHODS

We searched for all randomized controlled trials on this topic. A set of strict inclusion and exclusion criteria was developed. Six studies were meta-analysed together then in subgroups of topical tranexamic acid and intravenous aprotinin. We compared postoperative chest drain output, transfusions requirements and duration of hospital stay where available to determine the efficacy of topical tranexamic acid or intravenous aprotinin in reducing blood loss.

RESULTS

The use of antifibrinolytics reduces 24-h chest drain output (-290.21 mL [-524.75, -55.66], P = 0.02, I²  = 98%), red blood cell transfusion requirements (-1.27 units [-2.24, -0.30], P = 0.01, I²  = 100%) and shortened duration of hospital stay (-1.81 days [-3.25, -0.36], P = 0.01, I²  = 96%). The subgroup analysis also supported this trend.

CONCLUSION

We conclude that the use of antifibrinolytics appears to reduce postoperative blood loss by reducing chest drain output, transfusion requirements and length of stay after thoracic surgery.

The Coagulation Profile of End-Stage Liver Disease and Considerations for Intraoperative Management

The coagulopathy of end-stage liver disease results from a complex derangement in both anticoagulant and procoagulant processes. With even minor insults, cirrhotic patients experience either inappropriate bleeding or clotting, or even both simultaneously. The various phases of liver transplantation along with fluid and blood product administration may contribute to additional disturbances in coagulation. Thus, anesthetic management of patients undergoing liver transplantation to improve hemostasis and avoid inappropriate thrombosis in the perioperative environment can be challenging. To add to this challenge, traditional laboratory tests of coagulation are difficult to interpret in patients with end-stage liver disease. Viscoelastic coagulation tests such as thromboelastography (Haemonetics Corporation, Braintree, MA) and rotational thromboelastometry (TEM International, Munich, Germany) have helped to reduce transfusion of allogeneic blood products, especially fresh frozen plasma, but have also lead to the increased use of fibrinogen-containing products. In general, advancements in surgical techniques and anesthetic management have led to significant reduction in blood transfusion requirements during liver transplantation. Targeted transfusion protocols and pharmacologic prevention of fibrinolysis may further aid in the management of the complex coagulopathy of end-stage liver disease.

[The "Seville" Consensus Document on Alternatives to Allogenic Blood Transfusion. Sociedades españolas de Anestesiología (SEDAR), Medicina Intensiva (SEMICYUC), Hematología y Hemoterapia (AEHH), Transfusión sanguínea (SETS) Trombosis y Hemostasia (SETH)]

The Consensus Document on Alternatives to Allogenic Blood Transfusion (AABT) has been drawn up by a panel of experts from 5 scientific societies. The Spanish Societies of Anesthesiology (SEDAR), Critical Care Medicine and Coronary Units (SEMICYUC), Hematology and Hemotherapy (AEHH), Blood Transfusion (SETS) and Thrombosis and Hemostasis (SETH) have sponsored and participated in this Consensus Document. Alternatives to blood transfusion have been divided into pharmacological and non-pharmacological, with 4 modules and 12 topics. The main objective variable was the reduction of allogenic blood transfusions and/or the number of transfused patients. The extent to which this objective was achieved by each AABT was evaluated using the Delphi method, which classifies the grade of recommendation from A (supported by controlled studies) to E (non-controlled studies and expert opinion). The experts concluded that most of the indications for AABT were based on middle or low grades of recommendation, "C", "D", or "E", thus indicating the need for further controlled studies.

A comparison of transfusion requirements between living donation and cadaveric donation liver transplantation: relationship to model of end-stage liver disease score and baseline coagulation status

The use of living donation is an important option for patients in need of liver transplant. We retrospectively reviewed the preoperative Model for End-Stage Liver Disease (MELD) score, baseline coagulation laboratory results, and intraoperative transfusion of red blood cells and component therapy for 27 living donation transplants and 69 cadaveric donation transplants during a 3-yr period (2001-2004). Patients undergoing living donation transplantation had significantly lower MELD scores and preserved coagulation function compared with cadaveric donation transplantation recipients (P < 0.001). The living donation transplant patients also received significantly fewer transfusions of red blood cells and component therapy compared with the cadaveric donation transplant patients (P < 0.001). For the combined population of both cadaveric donation transplant and living donation transplant patients, there were significant associations between MELD score and preoperative coagulation tests (P < 0.001) and intraoperative transfusion of blood and component therapy. MELD score and preoperative fibrinogen concentration were identified as independent predictors of transfusion exposure. In conclusion, we detected significant differences in severity of disease at time of transplantation, degree of impairment of coagulation function, and need for transfusion of red blood cells and component therapy between patients undergoing living donation transplantation compared with patients undergoing cadaveric donation transplantation.

A review of aprotinin in orthotopic liver transplantation: can its harmful effects offset its beneficial effects?

Blood transfusion can adversely affect patient outcome and graft survival in orthotopic liver transplantation (OLT). With this respect, prophylactic aprotinin administration decreases blood loss, transfusion requirements, and the hemodynamic changes associated with graft reperfusion in patients undergoing OLT. However, data indicate limiting the use of aprotinin in OLT: (a) clinical, biological, echocardiographic, and postmortem findings recorded in patients with chronic liver disease or undergoing OLT suggest that a continuous prothrombotic state exists in these patients. Whether the inhibition of fibrinolysis associated with aprotinin therapy will expose some patients to untoward thrombosis is questionable; (b) aprotinin does not appear to alter postoperative outcome in patients undergoing OLT; (c) aprotinin decreases blood transfusion requirements only when surgery is associated with significant blood loss. However, at the present time, median transfusion requirements of 2 to 5 red blood cell units are required in OLT.

Antifibrinolytics in orthotopic liver transplantation: current status and controversies

This article reviews the current status and controversies of the 3 commonly used antifibrinolytics-epsilon-aminocaproic acid, tranexamic acid and aprotinin-during liver transplantation. There is no general consensus on how, when or which antifibrinolytics should be used in liver transplantation. Although these drugs appear to reduce blood loss and decrease transfusion requirements during liver transplantation, their use is not supported uniformly in clinical trials. Aprotinin has been studied more extensively in clinical trials and appear to offer more advantages compared to two other antifibrinolytics. Because of the diverse population of liver transplant recipients and the potential adverse effects of antifibrinolytics, especially life-threatening thromboembolism, careful patient selection and close monitoring is prudent. Further studies addressing the risks and benefits of antifibrinolytics in the setting of liver transplantation are warranted.

The effect of aprotinin on transfusion requirements in pediatric orthotopic liver transplantation

The use of aprotinin to reduce blood loss by inhibiting fibrinolysis thereby decreasing transfusion requirements during orthotopic liver transplantation (OLT), is well-documented in adults. We set out to test the hypothesis that the prophylactic use of aprotinin reduced blood product requirements during pediatric OLT. A retrospective study was performed, reviewing data from 24 OLTs performed over a 4-yr period. Six patients did not receive aprotinin (group 1), while 18 (group 2) received a weight-based dose of aprotinin. Both groups were comparable with respect to demographics, baseline characteristics and surgical variables except for a significantly more prolonged activated partial thromboplastin time (APTT) in the aprotinin group (p = 0.015). Despite the fact that median values for transfused volumes of red blood cells (78.3 vs. 36.7 mL/kg) and fresh frozen plasma (51.9 vs. 23.7 mL/kg) were more than halved in the aprotinin group, there was no statistical difference demonstrated. The failure to reach statistical significance can probably be explained by the small number in group 1 and a high level of scatter. All patients in group 1 required intraoperative transfusion of RBC and fresh frozen plasma (FFP) while two patients in group 2 did not require RBC and seven received no FFP. There were four patients in group 1 and 17 in group 2 who did not receive platelets while five in group 1 and 12 in group 2 did not receive cryoprecipitate. The differences between the groups in avoidance of these blood products did not reach statistical significance. There was little difference between groups with respect to albumin and crystalloid requirements. No statistical difference was demonstrated in intraoperative hematologic profiles between the two groups except during the anhepatic phase of surgery when there was a statistically significant more prolonged prothrombin time (p = 0.04) and a greater international normalized ratio (p = 0.027) in group 2.

Aprotinin reduces postoperative bleeding and the need for blood products in thoracic surgery: results of a randomized double-blind study

OBJECTIVE

Bleeding complications have been a major concern in certain thoracic surgery operations, especially decortication and pulmonary resection for inflammatory pulmonary infection. Prevention of plasminogen activation and fibrinolysis by aprotinin administration has been shown to reduce perioperative bleeding during operations associated with high blood consumption.

METHODS

Use of blood products (packed red cells, whole blood), chest tube drainage, analgesic requirement, chest tube duration for the patients undergoing major thoracic operations were recorded. In a double blind randomized fashion, patients were assigned to two groups receiving aprotinin (n=51) at a loading dose of 10(6) kallikrein inhibitory units (KIU) followed by an infusion of the same dose during chest closure or receiving placebo (n=52). On a daily basis, red-cell percentages of total fluid from drainage bottles were recorded and using the blood hematocrit level of the patient of the day before, the corrected value for the patient's blood volume equivalent of daily drainage was calculated.

RESULTS

There was a significant reduction in perioperative use of donor blood (0.98+/-0.92 vs. 0.45+/-0.32 unit; P=0.0026), and total chest tube drainage (corrected value for the corresponding blood volume) (28.2+/-36.9 vs. 76.9+/-53.3 ml, P=0.0004) (mean+/-standard deviation) in the aprotinin group. However, aprotinin did not reduce postoperative transfusion or decrease in hematocrit level due to thoracic operations. In high transfusion-risk thoracic surgery patients (patients who underwent decortication, pulmonary resection for inflammatory lung disease and chest wall resection), the perioperative transfusion was only 0.50+/-1.08 units in aprotinin group, compared with 1.94+/-0.52 units in control group (P=0.003). Postoperative transfusion was also reduced in aprotinin administrated group (0.53+/-0.56 vs. 1.38+/-0.97 units; P=0.02). The mean total blood loss was decreased to nearly one third of the blood loss of the control group (41+/-28 ml vs. 121+/-68 ml; P=0.001).

CONCLUSION

Aprotinin significantly reduced perioperative transfusion requirement and postoperative bleeding during major thoracic operations. Aprotinin decreased perioperative transfusion needs. Moreover, patients who were at risk of greater blood loss during and after certain thoracic operations had a greater potential to benefit from prophylactic perioperative aprotinin treatment.

Reduction of hepatic reperfusion injury by antithrombin III and aprotinin

Disturbance in hepatic microcirculation and leucocyte-endothelium interaction after warm ischaemia represents one of the leading mechanisms for postoperative organ dysfunction. Recent studies have shown that pretreatment with antithrombin III (AT III) and aprotinin reduces the leucocyte-endothelium interaction in ischaemic small intestine and during extracorporal circulation in cardiac surgery. Standardized warm hepatic ischaemia and intravital fluorescence videomicroscopy was performed in an experimental study with rats. Animals were pretreated with AT III or aprotinin. Analysis of intravital videomicroscopy showed that the hepatic microcirculation after warm hepatic ischaemia in rats was significantly enhanced by AT III and aprotinin, most likely by reducing the leucocyte-endothelium interaction. We concluded that drug application before the Pringle manoeuvre might reduce the reperfusion damage after liver resection.

[Changes in homeostasis during surgical liver resection]

OBJECTIVES

To assess changes in haemostasis during liver resection and to discuss the indications for antifibrinolytic therapy.

STUDY DESIGN

Open prospective study.

PATIENTS

The study included 39 consecutive non-cirrhotic patients presenting for liver resection under portal triad clamping.

METHOD

General anaesthesia was obtained with thiopentone, fentanyl, vecuronium and isoflurane. Transfusion scheme was standardized. Aprotinin (5,000 kIU.kg-1 BW) was administered in case of unexplained bleeding in the operative field. Coagulation pattern was assessed by routine tests and thrombelastrography before surgery, before portal triad clamping, 5 min after reperfusion and at completion of surgery. Patients requiring aprotinin intraoperatively were compared to others.

RESULTS

In 32 patients no significant bleeding occurred. Their coagulation pattern was moderately changed and remained within the normal range. In seven patients severe bleeding occurred which was treated with aprotinin. Their coagulation tests were significantly modified, especially after reperfusion, associating an increase in aPTT, TT, FDP, DDim, r + k and a decreased platelet count.

CONCLUSION

These changes were more in favour of a dilution coagulopathy or a DIC than hyperfibrinolysis. Therefore substitutive therapy with coagulation factors should be preferred to an antifibrinolytic agent. A systematic administration of the latter for liver resection in non-cirrhotic patients is debatable, considering the allergic risk (reoperation for cancer recurrence), thrombosis facilitation (pedicle clamping) and high cost.

An experimental study of the effect of aprotinin on intestinal adhesion formation

BACKGROUND

Depression of fibrinolysis is known to be a major mechanism for postoperative adhesion formation. Because aprotinin inhibits fibrinolysis it may lead to an increase in adhesion formation whereas its anti-inflammatory effects may lead to a decrease in adhesion formation. Our aim is to clarify conflicting results in previous literature.

METHODS

Basal levels of intestinal hydroxyproline (OHP) content and local fibrinolytic activity (LFA) were determined using naive groups. In the experiment groups, adhesions were created by scraping and creating a transient ischemia of a segment of terminal ileum. Group I and II rats were injected subcutaneous (s.c.) normal saline (NS) for 3 days and single dose intraperitoneal (i.p.) NS, respectively. Group III and IV rats were injected s.c. aprotinin for 3 days and single dose i.p. aprotinin, respectively. Group V rats were injected intramuscular methylprednisolone (MP) for 3 days. LFA and OHP levels were determined on the second and fifth postoperative days. The severity of adhesion formation was graded on the fifth day.

RESULTS

Aprotinin decreased both the severity of adhesions and OHP levels whereas MP decreased only the severity of adhesions. There was an early depression of LFA at the second day in both NS and MP groups increasing to basal levels at the fifth day. OHP levels showed significant correlation with adhesion severity.

CONCLUSION

Results showed that aprotinin decreased intra-abdominal adhesion formation probably by preventing early depression of LFA.

Continuous small-dose aprotinin controls fibrinolysis during orthotopic liver transplantation

Large doses of aprotinin (1,000,000-2,000,000 kallikrein inhibitor units [KIU] initial dose and a 500,000 KIU/h infusion) have been used during orthotopic liver transplantation (OLT) to reduce the incidence and severity of fibrinolysis. This double-blinded study was designed to investigate whether a small-dose infusion of aprotinin (200,000 KIU/h) would control fibrinolysis. A controlled study was undertaken to compare small-dose aprotinin with a placebo in patients undergoing OLT with veno-venous bypass. Forty-four patients were randomized either to the aprotinin group (n = 21), which received an intravenous infusion of 200,000 KIU/h without an initial dose, or to a control group (n = 23), which received normal saline. Coagulation variables, thrombelastograms, and postoperative blood drainage were measured. Blood levels of fibrin degradation products (FDP) were significantly higher in the control group (95% > 20 micrograms/mL) at the end of surgery compared to the aprotinin group (53% > 20 micrograms/mL, P < 0.01). The transfusion of cryoprecipitate units was more in the control group versus the aprotinin (12.6 +/- 12.8 vs 5.7 +/- 7.5; P < 0.04), as was the number of fresh frozen plasma units (6.6 +/- 3.5 vs 3.6 +/- 6.1; P < 0.05). We conclude that an infusion of a small dose of aprotinin can safely control fibrinolysis during liver transplantation with a concomitant reduction in transfusion of blood products.